Android Pay support has expanded to 60 new banks in the U.S., though it is worth noting that most of these are smaller banks and this has been the case for quite some time as most of the larger establishments have been support for a while. That said, there are lots of users who bank at smaller banks and credit unions for many different reasons, whether it's because they're local or perhaps for some other reason. Whatever the case may be if your bank hasn't supported Android up until now, then you'll want to check the Android Pay support list to see if your bank is now supported.
Included in the list of newly supported banks is Alabama Credit Union, Corydon State Bank, Generations Bank, Members Cooperative Credit Union, TwinStar Credit Union, and Wilson Bank & Trust. That is of course not 60 banks so there are a lot more included, and you can check the full list of supported banks from the link below.
Right now Android Pay is only available through your mobile device as a means for paying for goods and services at supported retailers, giving you a way to pay without having to reach for your physical wallet. In addition to that it's also possible to use Android Pay for mobile purchases online and in many different Android apps, like Uber for example. Google is rumored to be looking into expanding Android Pay to desktops though, which would likely be the same process as using Android Pay when checking out for an online purchase on your smartphone, but from the desktop instead. Whether or not Google actually brings Android Pay to desktops is uncertain but it seems that it has at the very least considered the idea and attempted to plan out how to best implement it. That said if it does end up on desktops it might not be that soon. If you've used Android Pay before it's worth giving it a shot as it's a simple method of payment, and sometimes Google gives incentives to users, like the promotion it's running Australia right now where people that use Android Pay when available are given the chance to win prizes.